Present radial motorcycle tyres have short sidewalls which extend to the tread edges radially and axially outwardly from the tyre beads. The beads provide engagement to the wheelrim on tapered bead seats. The sidewalls are reinforced by radial carcass plies which when tensioned by the inflation pressure act together with sidewall geometry to provide location of the curved tread regions to withstand cornering forces.
The sharply curved tread region of the conventional motorcycle tyre is specially reinforced by a reinforcing belt or breaker to give the required structural rigidity to allow for banking over of the motorcycle when cornering whilst giving sufficient flexibility to allow localized tread flattening in the ground contact patch for good road grip. Conventionally such a belt comprises two plies of tyre fabric each being reinforced by parallel cords disposed at an angle to the tyre circumferential direction with the cords crossed with respect to the adjacent ply.
Such tyres however, due to their uniform breaker structures, do not provide fully optimum stability and lateral grip.
A motorcycle tyre having in the tread region a bandage ply and in each tread edge region an additional reinforcing ply is known from EP-B-0 628 435. However in this known tyre the ply turnup edge extends fully radially outward to overlap the additional ply. However in such a structure the sidewall stiffness is increased which decreases riding comfort.
Therefore an object of the present invention is to improve the properties of such tyres.